Fashan's mother was worried in vain, but in fact, Zhang and his wife didn't care.

They had seen too many children fighting in that side of the world, and it could almost be seen as a need for the normal development of children.

Children who have never fought are pathetic------ such as the princes of the Great Song Dynasty, their upbringing environment is not normal.

Zhang is busy getting his camera, and the quality of optical glass production has now improved significantly.

It took them several years to find the process method of adding zinc oxide or lead oxide to achromatize, and to determine the constant of optical glass------ and the process data of that world is not suitable most of the time, so they can only find their own rules and methods.

According to the current level, Zhang designed a mirror-box wooden-frame camera.

This type of camera needs to be set up with a tripod wooden frame, a large wooden case installed, and the lens can be installed before it can be used.

The large case contains a three-layer black cotton linen mask, a control tenon on the right to adjust the exposure speed, and an exposure rope to pull the tenon on the left.

There is a negative box in the mirror box, and there is a gatekeeper pump on the box, and the sealing effect is quite good.

The gate pump is controlled by a V-shaped spring, and its exposure speed can also be adjusted.

Once the problem with the lens is solved, all that remains is the manufacture of the negative, developer, and fixer.

Regardless of the material of the negative, celluloid transparent negative is the most suitable, and gelatin and silver chloride are used for its coating liquid, because these two materials are easy to process.

The developer is mainly prepared with sulfuric acid, methanol and silver halide, and the preparation process must be recorded one by one, and then compared with the effect of development, so that the best ratio can be slowly found.

The fixer is relatively simple, just use crystalline sodium sulfate and acetic acid.

The first photograph was taken by the owner of the island himself, and he washed the bottom plate himself------ and he had to demonstrate the assistants he had recruited, and in the future, they would be the main personnel in the photography business, and this skill would need to be passed on by them.

He arched into the thick cover to shoot, savoring the reflection in the frame, his two hands outstretched, his right hand adjusting the tenon of the exposure speed, and his left hand pulling the exposure rope.

In the end, he chose the best time to pull the exposure rope, "click", and took a picture.

Then he waved his hand, and his two assistants carefully took out the box of negatives, put them in the box, and brought them back to the lab.

He led his two assistants directly into the wet area of the dark room, where the red-painted kerosene lamps had already been lit, and the contents of the room were shrouded in a hazy red.

There is also an assistant waiting for them.

Zhang said: "Soak both the developer and the fixer." ”

The two helpers opened the two different shapes of the medicine bottles, poured some powder into the white porcelain square plate, and then brewed them.

Zhang watched their movements with satisfaction, and said to the third assistant, "What should I pay attention to when brewing two kinds of medicine?" ”

The third assistant said: "The water temperature is just not hot, the developer is darker, and the fixer is transparent to the bottom." ”

They waited for the water temperature to drop down, and Zhang personally used a bamboo clip to hold the negative in the developer, and rinsed it back and forth in the developer at a frequency of once per second, and after thirty seconds, it was changed to two seconds again, and after another thirty seconds, he kept observing the pattern of the negative under the red light, feeling whether the contrast, density and tone of the pattern were moderate.

There is no way to teach them this technique all at once, not only does it take a certain amount of time to exercise on its own, but it also needs to be understood with heart.

But the general technical requirements are simple.

Zhang said: "The rinsing technique must be fast and gentle, so that there will be no bubbles. This stirring is small, the tone is too soft, and the contrast is too small; If there are many stirring times and the contrast is large, the shadow tone is harder. Observation of the negative can only be done once, we don't have any quality that is not very good, and it will be fogged badly if we observe it twice......"

The three assistants nodded in unison to indicate that they remembered.

After Zhang Island Master rinsed the negatives in the Qingshui Jar, he began to put the negatives into the fixer again.

He said happily: "The negatives must be rinsed cleanly, or they will not affect the tone of the film, and it is the same after the film, and you can't be lazy......"

Then he pointed to the wall clock on the wall and said, "It's best to control the fixing time to about thirteen minutes, which is the theoretical standard requirement."

The three assistants nodded in memory.

They are all young people selected by the Liuqiu Technical School, and their learning ability is good.

After the final version was washed and dried, Zhang Dao took a look at it, and it was good!

At this time, the scientific name of the negative plate is the negative photo, because the place that should be black is white, and the place where it should be white is black.

Zhang carefully stacked the negatives on the printing paper, pressed them on the printing camera glass, and after re-exposure, the next step was to go through the process just now.

Next, Zhang asked his assistant to do the process again...... After the bottom plate is washed out, I am not afraid.

Printing paper is a protein photo paper used, and to make this photo paper, it needs to be laminated twice.

The first is to make a protein coating, the necessary ingredients of which are egg white, table salt, purified water and 28% acetic acid.

After mixing them all, they were left in the shade for more than seven days, in fact, according to the observation of Zhang Islander, the longer the effect, the better.

The second lamination is a layer of silver nitrate, and the necessary ingredients are silver nitrate and purified water to control the contrast.

The lamination can be applied with a paintbrush, or by floating, allowing the paper to float on top of the solution.

Zhang Daozhu first used the second method, and did two protein coatings and one silver nitrate coating.

Later, he found that the silver grains were unevenly distributed, the maximum density was very low, and the effect was sandy.

Finally, he determined that the method of making primary protein and secondary silver nitrate coating would be better.

He didn't care about the rest of the matter, and let the three assistants carry the camera every day and take pictures in the Badaohe area until they reached the level.

You can't shoot a dynamic scene, but as long as you can stay still for three to five seconds, the exposure effect is still good.

After confirming that the camera and other necessary materials could be produced, Zhang was still concerned about the aspirin manufacturing of the quiet master's house.

He also knows that aspirin is more important than a camera------ antipyretic, analgesic and anti-inflammatory, especially in the treatment of rheumatoid arthritis, it has a good effect, and it may be the only synthetic drug in the world that has been clinically tested for more than 70 years.

Crucially, it is also relatively simple to refine and process.

It is easy to extract salicylic acid from willow bark and purify it, but this cannot be used directly, because direct salicylic acid will harm the oral mucosa and gastric mucosa.

It requires the addition of an acetyl group to modify salicylic acid------ but this process is always unstable, so the efficacy of the product is uncertain.

Zhang Daozhu directly suggested methods, one is exhaustive, and the other is to directly use people to test the medicine.

The quiet master was a little hesitant.

Zhang said: "Don't believe too much in the process instructions we brought, the current conditions are different, and we basically can't use their data, that is, to point out a direction."

We make medicine to save people, if there is any loss during the period, you can consider it as a normal price!

Think of it this way, it's all about a better life for our future generations------"

The quiet master couldn't help but nod in agreement.